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red7

Best jetting for my scenario.

14 posts in this topic

I'm doing a bunch of mods tonight which is why I have a few threads going....thanks for your help!

I have the carb off and am debating between jets. I'd like to get your advice on the best setup for me. Keep in mind that I'd like to get one "best all around" setup if that's possible even though my riding locations will change quite a bit. I'm ok with giving up a little bit of peak performance but I want to be sure that I don't damage the engine by getting into a too lean situation.

I currently live at 5000' with temps ranging from 50-90. I will be moving to Mexico later this year and will be living 8 months on the beach (sea level) in 80-90 degrees with humidity. The other 4 months I will be in Mammoth and Lake Tahoe California at around 5000-8000' and a dry 70-90 degrees.

I have the JD red needle at the 5th clip position and it recommends a 168 main up to 6000 and a 165 from 6000-9000. I didn't see anything about the pilot jet. Indy's recommended settings say 165 main and 48 pilot for my Mazatlan 8 month portion of the year and a 165 main and 45 pilot for my elevation portion. I'm confused why JD and Indy recommend different Mains. What are your thoughts? Should I stick with the stock 165/45 setup? 165/48? 168/48?

Also, did you guys do anything to the accelerator pump timing adjustment screw of just leave it be? I haven't heard many people mention it but JD recommends it.

THanks!

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for mexico, seems same climate and altitude as here!!!

I am using 168 main, 48 pilot, JD red#4 (or #5 depending on if temp and humidity drops).

If you are having serious issues with bog, adjust the AP squirt. If not, don't touch it.

With your jetting, there is really only one way to find out, that is trial and error. If only we had EFI.......

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So Matty, will I be able to find a happy medium for both Mexico and the mountains? I have a ZipTy screw so hopefully that will give me some flexibility. I don't mind trying out some different jets but I'm not sure I'll know how to interpret what the bike is doing and how that correlates to changing jets. Hopefully someone can tell me, "if you've got in an 168 and it's doing this then you'll want to go down to a 165 and if you have a 45pilot and you're experiencing this then you want to go up to a 48. You know what I mean.

I had a pain getting the carb out enough to access it so I'm hoping I won't have to do this too many times.

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All I can say is if it is lean, it will be asmatic, won't pick up speed easily, breathe hard, be hot. Easy to tell if lean.

If rich, it will stumble, sputter if real bad, but run cooler. It is hard to tell if slightly rich unless you change to a leaner setting and you get an improvement.

Now perfect, it will just explode in power, no hesitations, no fuss. You will know if you got it right. This is why it is good to have a play around with a few jet sizes. The needle will have the biggest effect on how your bike runs.

The pilot circuit corresponds to 0 - 1/4 throttle, needle 1/4 - 3/4, main 3/4 to full open. Ues these throttle settings as a guide to find out what you need to change.

Only change one thing at a time as each circuit is effected by them all.

With your jetting, I would leave the needle where it is when you go to Mexico, the pilot and main jets are very easy to change out when you get there. Just go with the 48pilot and 168 main. You might find the 165 is good enough for you depending on how modded your bike is. If you don't have an adjustable fuel screw, get one. They make pilot circuit tuning simple, and perfect pilot circuit will crispen up throttle response.

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I installed the adjustable fuel mixture screw last night. Does it more effect the pilot jetting portion (0-1/4 throttle), needle or main (3/4-full)? I know I'm going to have to play around with it but the more I know before I do it the better.

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Also, how much difference does the zipty FMS make from fully closed to fully open? This goes with what I asked in the previous post so depending upon which portion of the jetting it effects the most.....is it like having the zipty all the way in is like running a 45 while running it 3+ turns out is like going to the next size jet like a 48? These are just examples but I think you know what I'm trying to ask.

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Man, everyone must be too busy at work today. Oh, how I do not miss those days. :excuseme:

Any other suggestions before I throw it back together. I'm really debating between what JD recommends and Indy and still wondering how the zipty works.

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I installed the adjustable fuel mixture screw last night. Does it more effect the pilot jetting portion (0-1/4 throttle), needle or main (3/4-full)? I know I'm going to have to play around with it but the more I know before I do it the better.

Fuel mixture screw is for tuning the pilot circuit, how ever, it effects the needle and main circuits.

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Also, how much difference does the zipty FMS make from fully closed to fully open? This goes with what I asked in the previous post so depending upon which portion of the jetting it effects the most.....is it like having the zipty all the way in is like running a 45 while running it 3+ turns out is like going to the next size jet like a 48? These are just examples but I think you know what I'm trying to ask.

it makes a little bit of a difference, but any more than 3, 3 1/2 turns out, it doesn't do much at all. If your pilot is too small, turning the FMS all the way out won't make it flow any more. The range is like 1 turn to 3 turns out.

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Thanks guys! I called my local Yamaha and talked with the service guy and he wasn't big on the JD jet kit. He says that everyone they've installed has been impossible to dial in and the customer ended up going back to the stock needle. Maybe they just didn't want to take the time to get it dialed in...I don't know. YOu guys all rave about them so I'm sure it's worth a shot.

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One thing for sure is that it is over priced. But they do work, so not snake oil.

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My scenario changed so I'm resurrecting this thread. How far back do they keep these btw as I'll want to print this before they trash it.

I left Prescott (5200') and am currently staying at my parents in Phoenix (1200' I think) for a few weeks before we move to Mexico the 25th of October. I don't care so much about dialing it in perfectly here since I'll only be here a few weeks but I thought it would be a good learning experience to figure out how the elevation changed my ideal setup. I have been running the stock 165 main, 45 pilot setup with the Zipty at 2 turns out and the bike ran great at 5200'. I went for my first ride at this elevation today and noticed 2 things......it sometimes bogs when I snap the throttle (maybe 10% of the time) and I get popping when I go from full throttle to closed throttle which I may have gotten sometimes before but not as often.

Is there enough adjustment in the FM screw going from 2 to 3 turns to make a big difference or is it definitely time to go to a 48 pilot (which I am awaiting)? I asked this earlier but didn't get a definitive response. Is the difference of the FMS from closed to say 3 turns out equivalent to the next sized pilot or is it less or more? Or for my scenario, will going from 2 to 3 turns be like going from a 45 to 48 pilot? I will go out to 3 turns tomorrow but I just thought I'd ask here so I'm a little more informed.

Also, how does humidity effect things since Mazatlan is quite humid? Is it the same as heat? Am I reading Indy's chart right that the hotter it is the richer the bike runs and therefore the smaller the jets you use?

Thanks!

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I'd bet you're very lean on the main and could use a needle change at least one clip richer. If you're on an '05 or newer, I'd leave the pilot at 45 for now. First do the main and see how it goes, 168 or 170 there. Then do the needle and check the effects. If you go over 3 turns on the FS after that, then change the pilot...SC

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I'm on an 04 and I forgot to mention that I have the JD red needle on number 5. Do you still think I should change the main? I only noticed hesitation when I first blipped the throttle. 1/4-wide open ran great but part of that could be the hp gain from the lower elevation so maybe it would run even bettter 1/4-wide open changing something. I'm going to have to re-dial in wheelies because I almost flipped it right in the middle of a big intersection due in part to the increased power at lower elevation. Pretty dumb on my part.

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